1. Field of the Invention
This invention relates to the reaction product of adenine, alkoxylated amine and hydrocarbyldithiobenzoic acid and to an improved lubricating oil composition containing the reaction product which shows excellent friction reducing properties.
2. Description of the Related Art
In order to protect internal combustion engines from wear, engine lubricating oils have been provided with antiwear and antioxidant additives. The primary oil additive for the past 40 years for providing antiwear and antioxidant properties has been zinc dialkyldithiophosphate (ZDDP). U.S. Pat. No. 5,076,945 discloses a lubricating oil composition containing an amine salt of a dithiobenzoic acid. The amines used to prepare salts are long chain hydrocarbyl amines.
Oil additive packages containing ZDDP have environmental drawbacks. ZDDP adds to engine deposits which can lead to increased oil consumption and emissions. Moreover, ZDDP is not ash-free and contains phosphorus. Most current commercial engine oils contain reduced phosphorus due to the poisoning of the catalytic coverters by phosphorus. Various ashless oil additive packages have been developed recently due to such environmental concerns. However, many ashless additive packages tend to be corrosive to copper which leads to additional components in the additive package to protect against corrosion.
It would be desirable to have a lubricating oil additive which provides excellent antiwear, antioxidation, fuel economy and environmentally beneficial (less fuel, less phosphorus, i.e., less exhaust emissions) properties while at the same time protecting the engine from copper corrosion.